If you take 4 - $5000 dollar contracts (website, app, etc) in 1 year, you've made more then what you make now. If it takes you a full month to do each project and a full month to get that project, you still have 4 months left over to get creative.
The Flash IDE is very important on setting up graphics properly. There is a lot of functionality to be gained from the timeline. Program in whatever you want: Flex, FlashDevelop, Eclipse + FDT plugin etc, but you still want your symbols in the library to be able to be accessed and updated/edited easily.
Flash developers know quite a few tricks to get stuff to act as intended, so I would highly recommend a book on flash game design. I read one a few years back and it helped a lot with the intricacies.